Electrical distributing and control apparatus for dental instruments and the like



March 1Q, 1931. w, GQw|E ELECTRICAL DISTRIBUTING AND CONTROL APPARATUS FOR DENTAL INSTRUMENTS AND THE LIKE Filed Sept. 9. 1929 2 Sheets-Sheet l March 10, 1931. w. GOWIE 1,796,097

' ELECTRICAL DISTRIBUTING AND CONTROL APPARATUS FOR DENTAL INSTRUMENTS AND THE LIKE Filed Sept. 9, 1929 2 Sheets-Sheet 2 IIII 27c N 2 55 29 26a 20 O 5Zc I9 Fly. .3.

gwuenioz Patented Mar. 10, 1931 UNITED, STATES PATENT OFFICE WILLIAM GOWIE, OF CANTON, OHIO, ASSIGNOR TO THE HARVARD COMPANY, OF CANTON, OHIO, A CORPORATION OF OHIO ELECTRICAL DISTRIBUTING AND CONTROL APPARATUS FOR DENTAL INSTRUMENTS AND THE LIKE Application filed September 9, 1929. Serial No. 391,153.

; sistances, switch gear, and suitable connectors for a plurality of electrodental instruments, each of which may require a different voltage and a different current, and the switch panel being adapted for mount1ng on a dental unit.

The maximum voltages and amperes required to operate the usual elect-rodental instruments may be as follows:

Cautery 3 volts, 10.0 amps. Mouth and antrum lamps 12 volts, 0.16 amps. Syringe .12 volts, 1.5 amps. All other instruments, such as spatulas, root canal driers, pluggers,

etc 4 volts, 2.2 amps.

Due to the foregoing voltage and current differences, it has been customary to provide a separate transformer and a separate switch and cord for each instrument, and such equipment adds considerable to the total cost of the dental unit, and requires a relatively large total space on or near the unit.

On the other hand some of the instruments may be used in ordinary practice but once or twice a month. 7

The total space required for separate transformers and switches for the several one instrument with the wrong output connectors of the distributing and control apparatus will not damage the apparatus.

Accordingly the objects of the present improvements include the provision, particularly for use on a dental unit, of electrical distributing and control apparatus for clental instruments and the like, which shall be very compact and occupy a relatively small space, which shall include a'plurality of output connectors'each adapted for delivering under variable control a different voltage and/or current, and which shall be so arranged as to preclude damage thereto by inadvertent connection of an instrument with the wrong connectors.

These and other'objects are attained in the present improvements, as will hereinafter be set forth in detail and claimed.

A preferred embodiment of the invention is illustrated in the accompanying drawings forming part hereof, in which Figure l is a fragmentary side elevation of the improved electrical distributing and control apparatus for dental instruments and the like, detached from its mounting on a dental unit; 3

Fig. 2, a fragmentary rear elevation thereof; and

Fig. 3, a fragmentary diagrammatic View illustrating the electrical relationships of the several parts of the apparatus.

Similar numerals refer to similar parts throughout the several views.

The improved electrical distributing and control apparatus is indicated generally at 10 and includes a novel transformer 11, and a novel switch and resistance unit 12.

The transformer 11 includes a primary Winding 13, the terminals of which are adapted for connection with a standard 110 volt 6O cycle power line.

The secondary 14: of the transformer in cludes a coil 14a of relatively high resistance wire connected in series with a coil 14]) of relatively low resistance wire.

A conductor 15 connects the junction 16 between the ends of the secondary coils with one binding post 17 on theswitch and re sistance unit 12; a conductor 18 connects conductor 20 is covered with black colored with the binding post 21 to which the black.

common busbar 23.

the outer end of the high resistance coil 14a with another binding post 19 on the unit 12; and a conductor 20connccts the outer end of the low resistance coil 14?) with a binding post 21 onthe unit 12.

For convenience in assembly and mainte nance, the conductor is covered with yellow 1 colored insulation; the conductor 18 is covered with red colored insulation; and the insulation,

The switch and resistance unit 12 includes a panel 22 preferably of insulating material upon the rear and at the bottom 01"? which a common bus bar 23 is mounted and connects wire leads. v

For CQIIXGIHQDCQ in making rapid, conne tions with the several. instruments to be served by the switch and, resistance unit, three acks 24a, 24b, and 2 le-are mounted at the bottom of the panel 22,.and similar connector members 25a, 25b, antL25c, respectively, of the acks are connected with the At the upper end of the panel 22, variable resistances or rheostats 26a and 260- are mounted, and between the resistances 26aa11d.

26c and the bus bar 23, a variable resistance or rheostat 26? 1s mounted.

The rheostats are preferably of thcjwire wound type, and include respectively resistance coils 27a, 27b, and,2?c andv IOlTtLtlblfl,

contact arms 286;,2872, and 2&2, respectively. The contact-armsare mounted respect vely i on shafts 29a, 29b, and 2 9c,avhich extend thereof, and knobs 30a, 30b, and 300 7 shown) are; securedirespect velyon the outer from the location'ot the coils andarms on the back of the panel 22 through suitable hearing apertures (not ends of the shafts.

The other connector member 31a of the Oneterminal of the resistance coil 27?) connected with a terminal of a fuse 3 1, the other terminal of which is connected with the binding, po'st19,

Thecoils l laand areproportianed sothat the potential between the black conductor 20 and the. yellow conductor 15 is 4 volts, and the. potential between thefblack; conductor, 20 and the red conductor 18-is 12, volts.

The coil 27a; has a maximum resistance in the panel to the frontside.

14b of the transformer of 0.25 ohms and the coil 270 has a maximum resistance of 3.0 ohms; while the coil 27?) has a maximum resistance of 150 ohms.

Accordingly the potential between the cm nector. members of the jack 24a, served by theblack conductor 20 and the yellow con ductor 15 through the low resistance rheostat 26a is 4 volts, thus permitting a flow of a relatively heavy current, and the jack 24a is adapted for selective connection with a plug 35 at one end of a conductor cable, the other end of which is connected with a socket. A cauter'y may be inserted in the socket and served from the jack 24a.

The yellow conductor 15 having a common connection not only. with therotary. sir-111.2811 oi the low resistance rheostat 26a; but also with the rotary arm 280 of the highresistance rheostat26c, also delivers 4 vols under proper control to the jack 24c, and when the plug 35 is inserted in this jack, instruments such'as a plugger requiring 4 volts anda relatively low amperage may be served.

If by mistake the plug 35 is inserted in the jack 240 when the cautery, is connected with the plug, no damage will bedone, be cause of, the relatively high resistance of the. rheostat 26c.

It is apparent that both rheostats 26a and 260 are served by the same conductors from the transformer, and that the jacks 24a and 24c served thereby deliver different currents at the same voltage, and that the operation of one rheostat has no effect on the other, the contact arms and coils being in parallel.

The potential between the connector members of the jack 24b is 12 volts for serving a; mouth la1np'conne'cted with the plug 35, and the fuse 34.1 rotects the transformer in the event that the cautery is plugged; into the,12 volt1-jack24b by mistake. 7

If the lamp is plugged incither, of the 4 volt, jacks, nodamage will be done, and the lamp-willonlybe partially illuminated.

I claim: I

1. Electrical distributing and control apparatus for dental instruments and the like includinga transformer anda switch unit, the switch unit including aiplurality of sets. ofcontact members, and a variable resistance for each set of contact. members, and the transformer including a primary and a sec.-

ondary, a conductor connecting one contact member of-each set with the similar contact members ofthe-otherE setsjand withone tor:

2. Electrical distributing and control apparatus for dental instruments and the like including a transformer and a switch unit, the switch unit including a plurality of sets of contact members, and a variable resistance for each set of contact members, the transformer including a primary and a secondary, a conductor connecting one contact member of each set with the similar contact members of the other sets and with one terminal of the transformer secondary, the variable vresistances including members movable with respect to each other, and a conductor connecting the other terminal of the transformer secondary with one of the members of one of the variable resistances, a conductor connecting similar members of some of the variable resistances with each other and with an intermediate point on the transformer secondary coil, and conductors each connecting another member of each variable resistance with the other contact member of the sets, respectively.

3. Electrical distributing and control apparatus for dental instruments and the lilre including a transformer and a switch unit, the switch unit including a plurality of acks, and a variable resistance for each jack, and the transformer including a primary and a secondary, a conductor connecting one contact member of each jack with the similar contact members of the other jacks and with one terminal of the transformer secondary, the variable resistances including members movable with respect to each other, a conductor connecting similar members of a plurality of the variable resistances with each other and with another point on the transformer secondary coil, and conductors each connecting another member of each variable resistance with the other contact member of the jacks, respectively.

Electrical distributing and control apparatus for dental instruments and the like including a transformer and a switch unit, the switch unit including a plurality of jacks,

and a variable resistance for each jack, the

transformer including a primary and a sec ondary, a conductor connecting one contact member of each jack with the similar contact members of the other jacks and with one terminal of the transformer secondary, the variable resistances including members movable with respect to each other, and a conductor connecting the other terminal of the transformer secondary with one of the members of one of the variable resistances, a conductor connecting similar members of some of the variable resistances with each other and with an intermediate point on the transformer secondary coil, and conductors each connecting another member of each variable resistance with the other contact member of the jacks, respectively.

5. Electrical distributing and control apparatus for dental instruments and the like including a transformer and a switch unit, the switch unit including a plurality of sets of contact members, and a variable resistance for each set of contact members, the transformer including a primary and a secondary, the secondary including a relatively high resistance coil connected in series with a relatively low resistance coil, a conductor connecting one contact member of each set with the similar contact members of the other sets and with one terminal of the transformer sec ondary, the variable resistances including members movable with respect to each other, and a conductor connecting the other terminal of the transformer secondary with one of the members of one of the variable resistances, a conductor connecting similar members of some of the variable resistances with each other, and with the connection between the high resistance coil and low resistance coil of the transformer secondary, and conductors each connecting another member of each variable resistance with the other contact member of the sets, respectively.

6. Electrical distributing and control ap-H paratus for dental intruments and the like including a transformer and a switch unit, the switch unit including a plurality of jacks, and a variable resistance for each jack, the transformer including a primary and a secondary, the secondary including a relatively high resistance coil connected in series with a relatively low resistance coil, a conductor connecting one contact member of each jack with the same contact members of the other jacks and with one terminal of the transformer secondary, the variable resistances including members movable with respect to each other and a conductor connecting the other terminal of the transformer secondary with one of the members of one of the variable resistances, aconductor connecting similar members of some of the variable resistances with each other and with the connection between the high resistance coil and the low resistance coil of the transformer secondary, and conductors each connecting another member of each variable resistance with the other contact member of the jacks, respectively.

In testimony that I claim the above, I have hereunto subscribed my name.

WVILLIAM GOWVIE. 

